The present invention generally relates to shotshell casings and more particularly to a compression formed shotshell having an integral collapsible basewad at the head end of the shotshell.
Compression formed shotshells have been well known for over 25 years. Such shotshells are exemplified by the shotshells and forming methods disclosed in U.S. Pat. Nos. 3,164,090, 3,176,614, and 3,351,014 issued to Metcalf et al. In the conventional compression forming process, a blank of high density polyethylene is formed preferably by injection molding. This blank is then compressed in a die such that the sides of the blank are extruded to form the elongated case wall portion and the remainder of the blank is formed into the basewad portion. A metal head is generally installed over the base portion either before or after compression forming and the open end of the compression formed shell casing trimmed to the proper length. This method of case formation generates an inexpensive, one piece shotshell casing that is waterproof and has the required sidewall strength to withstand the extreme pressures developed during propellant ignition. Shotgun shooters who infrequently practice their sport generally learn to tolerate the strong recoil that accompanies each shotshell firing. However, this recoil is still a significant concern especially to competitors and to those who fire a significant number of shotshells during trap and skeet practice. Butt pads and padded shoulders on shooting jackets have been developed to help absorb this recoil. There is always a need to reduce the recoil felt by the shooter, especially for those who shoot extensively.
One approach to reducing recoil is a shotshell which has a collapsible basewad as is described in U.S. Pat. No. 4,970,959, assigned to the assignee of the present invention. The collapsible basewad is formed with an external circumferential channel which, when inserted into the tubular shell casing, forms an annular cavity inside the case which collapses upon propellant ignition to reduce pressure and absorb some of the force which produces recoil. This collapsible basewad is preferably used with Reifenhauser tubing. However, this basewad cannot be used in a compressioned formed shotshell. Hence there is a need for a compression formed shotshell which produces reduced recoil for a given load.